Field of the Invention
Various embodiments of the present invention relate to a front axle of a vehicle, which includes a structure through which grease can flow at a connection portion between a king pin and a knuckle, in order to reduce vibration.
Description of Related Art
FIG. 1 schematically illustrates a connection structure between a front axle and a steering wheel which are applied to a vehicle or particularly a commercial vehicle. When a driver operates a steering wheel 1, the steering force is transmitted to a gear box 3 through a column shaft 2. Then, the steering force is increased by a hydraulic pressure or driving force of a motor, and transmitted to a tie rod 6 through a drag link 4. The steering force transmitted to the tie rod 6 rotates a knuckle 7 which is rotatably installed on the axle 5, and steers a front wheel of the vehicle.
FIG. 2 illustrates the connection portion between the axle 5 and the knuckle 7. Referring to FIG. 2, the axle 5 and the knuckle 7 are hinge-coupled through a king pin 8. The king pin 8 passes through the axle 5 and the knuckle 7, and filled with lubricant oil such as grease G for smooth rotation of the knuckle 7 and the axle 5. At the upper portion of the king pin 8, a space formed between an upper cover 9 and a taper bearing 11 is filled with grease G. At the lower portion of the king pin 8, a space formed between the lower end of the king pin 8 and a lower cover 10 is filled with grease G. Thus, when the knuckle 7 is rotated with respect to the axle 5, the grease G may reduce friction. In order to prevent leakage of the grease G, seals 13 are installed on the top and bottom surfaces of the portion to which the axle 5 is connected.
Between the lower portion of the king pin 8 and the knuckle 7, a king pin bushing 12 is installed. The king pin bushing 12 may be worn out by an external force generated by a steering operation or a bump during operation. Thus, a gap may occur between the king pin bushing 12 and the king pin 8. The gap causes vibration when the vehicle is braked. The vibration may be transmitted to the steering wheel 1 such that the driver feels the vibration.
In order to reduce the vibration, a separate damper is installed between the axle 5 and the knuckle 7. However, when the damper is added, the cost may be increased, and a space for installing the damper must be secured.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.